12 Technological Innovations from World War I

Despite its immense devastation, World War I also catalyzed significant technological breakthroughs that left a lasting legacy on society. Below, we explore 12 key innovations that emerged from World War I.

1. Tanks

In 1914, the anticipated “war of movement” envisioned by European military leaders quickly devolved into an unforeseen and seemingly endless war of trenches. Defenders, armed with machine guns and concentrated rifle fire, decimated advancing troops by the thousands before they could cross the deadly expanse of “no-man’s-land.”

The breakthrough came with the rise of the automobile, which had captivated the world since 1900. By equipping a heavily armored vehicle with a compact internal combustion engine running on diesel or gasoline, it became possible to advance under heavy gunfire. Adding powerful weaponry and replacing wheels with rugged treads for rough terrain gave birth to the tank.

2. Flamethrowers

While ancient civilizations like the Byzantines and Chinese employed primitive flame-based weapons, the modern flamethrower was conceptualized by Richard Fiedler, who presented his design to the German Army in 1901. The devices were rigorously tested by a specialized German unit in 1911.

However, their full effectiveness became evident in trench warfare scenarios. Following large-scale offensives, enemy troops often retreated into bunkers and dugouts carved into trench walls. Unlike grenades, flamethrowers could eliminate (i.e., incinerate) adversaries in these tight spaces without damaging the structures, which could later be repurposed by the advancing forces. The flamethrower was first deployed by German soldiers near Verdun in February 1915.

3. Poison Gas

Chemical weapons were employed by both sides with catastrophic effects during World War I. The Germans led the way in large-scale chemical warfare with an attack on Russian forces on January 31, 1915, during the Battle of Bolimov. However, freezing temperatures caused the toxic agent (xylyl bromide) to solidify in the artillery shells.

The initial effective deployment of chemical weapons took place on April 22, 1915, near Ypres, where German forces released chlorine gas from large canisters targeting French colonial troops' trenches. Although the defenders retreated, this did not lead to a decisive victory, as the Germans hesitated to advance, the gas dispersed, and Allied forces quickly reestablished their positions. Soon after, the Allies also began utilizing poison gas, and both sides developed increasingly toxic compounds to counteract gas masks, another wartime innovation. Ultimately, this escalation caused immense suffering without significantly altering the war's strategic outcomes—a recurring pattern throughout the conflict.

4. Tracer Bullets

Although much of World War I was marked by futile efforts, nighttime combat was particularly inefficient due to the inability to track gunfire. This changed with the British development of tracer bullets, which contained a flammable substance that created a glowing trail. The initial 1915 version was unreliable, with an inconsistent trail limited to 100 meters. However, the 1916 model, the .303 SPG Mark VIIG, produced a steady bright green-white trail and became highly effective. Its success was partly due to an unintended advantage: the flammable material could ignite hydrogen, making it ideal for targeting German zeppelins that were conducting raids over England.

5. Interrupter Gear

When World War I began, airplanes had only existed for about a decade. Although their potential for combat was evident, particularly as platforms for bombs and machine guns, the challenge of firing a machine gun without hitting the propeller blades remained unresolved. Initially, the U.S. Army experimented by securing a gun to the plane with a leather strap, pointing it downward and operated by a gunner seated next to the pilot. This setup was impractical for aerial combat and inefficient, as it required two crew members.

An alternative approach involved positioning the gun above the pilot to avoid the propeller, but this made aiming difficult. The breakthrough came when Swiss engineer Franz Schneider patented an interrupter gear concept in 1913. Dutch designer Anthony Fokker later developed a functional version, known as the “synchronizer,” which used a cam connected to the propeller shaft to enable machine guns to fire between the spinning blades. The Germans implemented Fokker’s design in May 1915, prompting the Allies to create their own versions. Schneider eventually filed a lawsuit against Fokker for patent infringement.

6. Air Traffic Control

During the early days of aviation, pilots were completely cut off from ground communication once airborne, relying only on visual signals like flags or lamps. This limitation was overcome by the U.S. Army, which introduced the first operational two-way radios in aircraft during World War I, even before the U.S. officially entered the conflict.

The development of these radios began in 1915 in San Diego. By 1916, technicians achieved radio telegraph transmissions over 140 miles, and in-flight communication between planes became possible. A significant milestone was reached in 1917, when a pilot's voice was successfully transmitted via radio from an airborne plane to a ground operator.

7. Depth Charges

The German U-boat offensive inflicted massive losses on Allied shipping, destroying millions of tons of cargo and claiming tens of thousands of lives. To counter this threat, the Allies developed the depth charge—an underwater explosive deployed from ships using catapults or chutes. Depth charges were equipped with a hydrostatic pistol that triggered detonation at specific depths based on water pressure, ensuring they wouldn’t harm surface vessels, including the deploying ship. Conceptualized in 1913, the first functional depth charge, the Type D, was created by the Royal Navy’s Torpedo and Mine School in January 1916. The U-68 became the first U-boat destroyed by a depth charge on March 22, 1916.

8. Hydrophones

Locating U-boats became significantly easier with the invention of hydrophones, underwater microphones that detected sound waves. The first hydrophone was developed by Canadian inventor Reginald Fessenden in 1914, initially intended to locate icebergs after the Titanic disaster. However, its utility was limited as it could only measure distance, not direction.

The hydrophone was further enhanced by French physicist Paul Langevin and Russian engineer Constantin Chilowsky, who created an ultrasound transducer using piezoelectricity. This device utilized a quartz layer sandwiched between metal plates to detect minute changes in water pressure caused by sound waves, enabling users to determine both the distance and direction of underwater objects. The hydrophone achieved its first U-boat kill in April 1916. Later advancements by American engineers allowed detection of U-boats up to 25 miles away.

9. Aircraft Carriers

The first instance of an airplane taking off from a moving ship occurred in May 1912, when Commander Charles Rumney Samson flew a Short S.27 pontoon biplane from a ramp on the HMS Hibernia in Weymouth Bay. However, the Hibernia wasn’t a true aircraft carrier, as planes couldn’t land on its deck; instead, they had to land on water and be recovered, significantly slowing operations.

The first genuine aircraft carrier was the HMS Furious, initially built as a 786-foot battle cruiser with two massive 18-inch guns. However, concerns that the guns could damage the ship led to its redesign. Engineers added a long platform for launching and landing aircraft, with planes stored in hangars beneath the runway, a design still used today. Squadron Commander Edward Dunning made history by becoming the first to land a plane on a moving ship, successfully touching down a Sopwith Pup on the Furious on August 2, 1917.

10. Pilotless Drones

The first drone without a pilot was created for the U.S. Navy between 1916 and 1917 by inventors Elmer Sperry and Peter Hewitt. Initially conceived as an unmanned aerial bomb, it served as an early version of a cruise missile. The Hewitt-Sperry Automatic Aircraft had a wingspan of 18.5 feet, a 12-horsepower engine, and weighed 175 pounds. It used gyroscopes for stabilization and a barometer to measure altitude.

The world's first unmanned flight took place on Long Island on March 6, 1918. However, its targeting method—simply pointing and flying—proved too inaccurate for effective use against ships during the war. Development continued post-war with attempts to incorporate remote radio control, but the Navy abandoned the project in 1925.

11. Mobile X-Ray Machines

With millions of soldiers enduring severe, life-threatening injuries during World War I, the demand for X-rays—revolutionary tools for medical diagnostics—was immense. However, traditional X-ray machines were large, cumbersome, and too fragile to transport.

Marie Curie stepped in, developing mobile X-ray units for the French military shortly after the war began. By October 1914, she had equipped cars and small trucks with X-ray machines, enabling them to visit frontline surgical stations. By the war's end, 18 of these mobile units, nicknamed “Little Curies,” were in operation. Later, in 1919, Frederick Jones created a more compact portable X-ray machine. Jones also pioneered refrigeration units, air conditioning systems, and the self-starting gasoline lawnmower.

12. Sanitary Napkins

Throughout history, women have used various makeshift solutions for menstrual hygiene, from washable cloths to ancient Egyptian papyrus. However, the modern sanitary napkin emerged thanks to cellulose-based bandage materials developed during World War I. French nurses quickly realized these clean, highly absorbent bandages were far more effective than previous methods.

The practice spread to British and American nurses, and soon caught the attention of businesses. In 1920, Kimberly-Clark launched the first commercial sanitary napkin, Kotex (a blend of “cotton” and “texture”). Initial challenges arose as publications refused to advertise the product. It wasn’t until 1926 that Montgomery Ward broke the taboo by featuring Kotex in its widely-read catalogue.